Each of a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) and an IGBT (Insulated Gate Bipolar Transistor) is a semiconductor device that controls conduction and interruption of current based on a predetermined threshold voltage. For example, Japanese Patent Laying-Open No. 2001-144288 (hereinafter, referred to as Patent Document 1) proposes a MOSFET using silicon carbide as its material. In this MOSFET, a p type base region (body region) having a hexagonal planar shape is formed within an n type epitaxial growth layer formed on a silicon carbide substrate, and an n type source region having a hexagonal planar shape is formed inwardly of the p type body region.